LV阀运行中卡涩的原因分析与解决

某电厂因供热形势原因满负荷运行,无法提高机组负荷以提高蒸汽量,必须关闭LV阀以提高供热汽量,该阀在小开度位置进行调整后频繁出现卡涩现象,严重影响机组的安全经济运行。通过对LV阀的解体检查,发现阀板驱动端边缘与阀体已发生刮擦,结合阀门其他部位解体情况,分析并解决了该问题。     

东汽1000MW机组高压调节汽阀十字头损坏分析及处理

某电厂#3、#4机组为东方汽轮机厂生产的1000MW超超临界空冷机组,在机组投运后相继发生2起门杆防转销脱落、2起高压调节汽阀阀杆脱落,阀门突关突开事件,造成机组负荷波动以及限负荷等严重威胁机组安全的事件.利用机组临修时间,对高压调节阀进行解体检查,发现十字头损坏并处理同时提出改造方案,以确保阀杆与十字头连接可靠性,为机组的安全可靠运行提供了有力保障.     

三联热电厂#2机CV阀改造分析

东糖集团三联热电厂#2机组CV阀是控制#2机组对外工业抽汽的汽量、压力与汽轮机低压缸进汽量分配的重要阀门,在运行中出现故障概率较大;由于CV阀是连接汽轮机高中压缸与低压缸的连接阀门,在运行时不能在线检修,对机组的运行存在极大隐患。文章对三联热电厂#2机CV阀改造进行了分析。     

调节阀用常温密封填料结构分析及改进

介绍了调节阀密封填料在阀门运行中出现阀杆处介质外漏,而对用户及阀门制造厂产生一定的能源损失、经济损失及声誉产生的不良影响,鉴于此种情况而对阀用密封填料的结构进行改进,改进后的密封填料,有效的解决了以上问题。     

330MW汽轮机组中压联合汽阀调节阀杆漏汽处理浅析

中电荔新电厂2×330MW机组均采用东方汽轮机厂生产的CC330-16.67/3.5/1.0/538/538型单轴双缸双排汽一次中间再热双抽供热凝汽式汽轮机。文章针对东方汽轮机厂生产的330MW中压联合汽阀调节阀杆漏汽的现象,对泄漏的调节阀体进行解体检查,并采取相应的处理措施,通过发现设备异常及技术分析,找到解决阀杆漏汽问题的方法,彻底处理好门杆漏汽缺陷。     

浅析液压驱动式SDV阀的调试

当前自动化控制系统的可靠性及稳定性越来越高,安全性在自动化生产过程中尤为重要。其中SDV(shutdown valve)阀主要用于ESD(Emergency shutdown system)系统中,为了保护设备,一般在设备的进出口处设置SDV阀,确保操作的安全性。文章结合阿布扎比原油管道项目中液压型SDV阀的应用为实例,对液压型SDV阀的安装与调试进行了具体分析和探究,供相关技术人员在遇到同类型的阀门安装调试时作参考。     

浅谈火电厂阀门泄漏综合治理

针对阀门发生漏泄时对火电厂机组运行存在很大危害,进行了在运行状态下和机组启、停前检查阀门的泄漏情况进行原因分析,在检修工艺、运行操作、漏泄治理等方面提出改进措施,是非常重要的,为各火电厂进行阀门漏泄治理提供借鉴。     

9FA燃料清吹系统问题分析和技术改进

针对晋江燃气电厂燃料清吹系统出现的问题进行细致分析,并从中进行了相应的改造,如增加阀门开关计时时间、增加阀间压力显示、用模拟量判断代替限位开关和电磁阀外移等相关改造,通过这些技术改进措施,提前发现设备存在的问题,防患于未然。     

300MW机组高压调节汽阀阀杆脱落的故障分析与处理

高压调节阀是汽轮机调速系统执行机构的主要设备元件,调节阀工作正常与否直接影响机组的安全稳定运行[1]。文章针对某电厂出现的高压调节汽阀阀杆脱落的故障事件进行了原因分析,最终通过对高压调节汽阀的改造,彻底解决了故障问题。     

电动楔式闸阀的研发与应用研究

随着超(超)临界火电机组的发展,对闸阀提出了更高的要求,有必要对应用于超(超)临界火电机组的闸阀进行深入的研究。文章结合武锅阀门公司闸阀研制实际,对超(超)临界火电机组中电动楔式闸阀的研发和应用进行了分析,具有一定的借鉴价值。     

倒流防止器装置过流件结构与能量损耗分析

文章在论述止回阀构成的倒流防止器装置结构及工作原理基础上,分析各类止回阀流态与流阻关系,并根据各止回阀过流结构的流阻系数,进行能量损失分析与计算,提出单蝶板型倒流防止器装置具有显著的节能效果,是一种很好的止回阀倒流防止器装置过流部件。     

减温减压阀节流套筒节流降噪分析研究

文章阐述了减温减压阀的工作原理、机械噪声对机组运行的影响、减温减压阀节流套筒的节流特性,进行了节流套筒可降低噪声量数值计算,对于保持减温减压阀自身安全稳定运行及工人的身心健康都有重要的意义。     

莆田2#燃机试运缺陷分析处理与总结

莆田燃气电厂在2#机分部试运和总启动过程中,出现了天然气关断阀卡涩、燃机末级叶片温度过高跳机、燃机BPT温差过大造成跳机、IGV阀位偏差大等事故,严重影响了机组的正常调试和安全运行。本文将重点分析2#燃机在启动调试过程中发生问题的原因、处理方法及从中得到的经验教训与总结,希望能对以后同类型机组的安装起到一定得指导性作用。     

考虑框——剪结构与基础相互作用的箱形基础优化设计

针对上部结构是框架－剪力墙结构体系的情形,建立了箱基、土体与上部结构相互作用的空间分析模型。以箱基主要材料造价为目标函数,以现行规程的设计计算规定和构造要求为约束条件,建立了箱基优化设计数学模型,并采用子空间组合算法进行减维处理。文末通过算例显示了剪力墙不同布局方式对箱基优化结果的影响。     

太仓港电厂磨煤机入口一次风隔绝门改造

针对太仓港电厂330MW机组磨煤机入口一次风隔绝门关不严、卡涩的情况,对一次风隔绝门进行了改造,成功的解决了一次风隔绝门关闭不严和备用磨煤机磨内温度过高的问题,不仅确保了磨煤机内部检修工作的顺序进行和提高了检修工作的安全性,同时也减少了热污染和漏风,改造效果显著。     

Tricks with the BoD model and an application to the e-Government Development Index

In this paper we examine the implications of the ideal and the anti-ideal decision-making units on the Benefit-of-the-Doubt (BoD) model. In particular, we verify that, in the presence of an ideal (anti-ideal) decision-making unit, the efficiency scores of the BoD (inverted BoD) model can be obtained without solving the relevant linear programming problems. In this case, it suffices to choose the largest (smallest) of the element-wise divided component indicators of the evaluated decision-making unit by those of the ideal (anti-ideal) decision-making unit. We then illustrate one practical use of this simple enumeration algorithm by providing empirical results for a BoD-based e-Government Development Index within a traffic-light reporting system.     

Testing for unit roots in the presence of uncertainty over both the trend and initial condition

In this paper we provide a joint treatment of two major problems that surround testing for a unit root in practice: uncertainty as to whether or not a linear deterministic trend is present in the data, and uncertainty as to whether the initial condition of the process is (asymptotically) negligible or not. We suggest decision rules based on the union of rejections of four standard unit root tests (OLS and quasi-differenced demeaned and detrended ADF unit root tests), along with information regarding the magnitude of the trend and initial condition, to allow simultaneously for both trend and initial condition uncertainty.     

On the Behaviour of Phillips–Perron Tests in the Presence of Persistent Cycles

In this paper, we analyse the impact of persistent cycles on the well‐known semi‐parametric unit root tests of Phillips and Perron (1988, Biometrika, Vol. 75, pp. 335–346). It is shown, both analytically and through Monte Carlo simulations, that the presence of complex (near) unit roots can severely bias the size properties of these tests. Given the popularity of these tests with applied researchers and their routine presence in most econometric software packages, the results presented in this paper suggest that practitioners should treat the outcomes of these tests with some caution when applied to data which display a strong cyclical component.     

尼龙阀芯单向阀替代不锈钢锥阀芯单向阀可行性分析

本文从市场应用、成本、可靠性等多方面分析了尼龙阀芯PA66单向阀替代不锈钢锥单向阀的可能性,通过和市场上常见的几种阀芯在不同冷媒中的浸泡试验以及长期运行试验等得出结论,尼龙阀芯单向阀在在R410a新冷媒中性能稳定,存在较大成本优势,可以替代加工工艺复杂且成本较高的不锈钢锥单向阀。     

Variance ratio tests of the seasonal unit root hypothesis

In this paper we develop tests of the seasonal (quarterly) unit root null hypothesis which reject in favour of stationarity for small values of certain variance ratio statistics, similar to those used by Canova and Hansen (J. Bus. Econom. Statist. 13 (1995) 237) in a different testing context. We demonstrate that our proposed statistics have pivotal limiting distributions under both the null and near seasonally integrated alternatives even when we allow for the possibility of both weak dependence and periodically heteroscedastic behaviour in the driving shocks. This is in contrast to the popular regression-based lag-augmented seasonal unit root tests of Hylleberg et al. (J. Econometrics 44 (1990) 215). A simulation study into the finite sample size and power properties of our proposed tests suggests that they display far superior size properties and, overall, broadly comparable power properties to the corresponding tests of Hylleberg et al. (J. Econometrics 44 (1990) 215), implemented with data-based lag augmentation. The results for the variance ratio tests at the seasonal harmonic frequency are particularly encouraging.